コバルト電析膜の残留歪みに及ぼすDC，PCおよびPR電解条件の影響

抄録

Using a plating solution containing CoSO₄•7H₂O, NaCl and H₃BO₃, direct current electrolysis (DC), pulsed current electrolysis (PC), and periodic reverse current electrolysis (PR) were used for cobalt deposition. DC increased in the range of －0.1 A/dm² to －10 A/dm². The minimum internal strain was 62×10⁶ under －2.0 A/dm². For PC, the internal strain was 62×10⁶ to 84×10⁶. For PR, the internal strain was 26×10⁶ to 29×10⁶, which was less than that of either DC or PC. It changed cyclically from tensile strain during deposition to relaxation during anodic dissolution of cobalt deposits. The surface morphology was investigated using scanning electron microscopy. Fine grain surfaces were observed in DC and PC. For PR, the surface morphology influenced the poorly defined hexagonal Co crystal. The X-ray diffraction pattern of the cobalt deposits can be obtained under both DC and PC. Both fcc {110} and hcp {11•0} structural planes were investigated during deposition. Especially, the fcc was formed originally. Then the fcc transformed drastically into the hcp. These grains spontaneously relaxed desorption of hydrogen with cobalt produced by the hydrogenated deposits. However, using PR, the hcp was different {10•0}, {10•1}, and {10•3} planes.